sale_restrict_price_b/security/restrict_saleprice_b.xml

<?xml version="1.0"?>
<openerp>
      <data noupdate="1">
          <record model="res.groups" id="groups_restrict_price_b">
              <field name="name">Permitir vender por debajo del precio B</field>
          </record>
      </data>
</openerp>